Measurement of Liquid Coefficient of Viscosity Using Liquid Surface Wave

Abstract

Surface waves are generated at the micron scale using disturbances of appropriate size. When the laser beam irradiates the liquid surface waves with different amplitudes, the optical effects of diffraction and reflection are observed respectively. On this basis, two methods, laser diffraction method and laser slope method, are proposed to measure the viscosity coefficient of liquid. This experiment takes water as an example. For the laser diffraction method, the relationship between the liquid viscosity coefficient and the liquid surface wave attenuation coefficient and wave number is theoretically derived. The experimental setup is given, and high visible diffraction patterns are observed on the screen. The attenuation curve of liquid surface wave is obtained by the relationship between diffraction fringes and surface wave. By studying the diffraction phenomenon of laser oblique incident surface wave, the viscosity coefficient of water is measured. For the laser slope method, the liquid viscosity coefficient is measured by studying the reflection of liquid surface wave with larger amplitude. Compared with capillary method and ball drop method, these two methods are real-time and non-contact for measuring low viscosity coefficient of liquid